The destination retailer that focuses on the diaper set just inked a 10-year deal to take 38,212 square feet at the Chelsea Centro.

The residential rental building at 200 West 26th Street is across the street from Whole Foods in the Chelsea Mercantile condo, and a block from the new Sixth Avenue rental corridor.

“They are making an investment in a growing market and I think they are right,” said H. Henry Elghanayan, a principal of Rockrose Development Corp., which owns both buildings.

Rockrose originally cut a deal for the Chelsea Centro space in September 2000 with Lechter’s Home Stores prior to its bankruptcy, and already has Commerce Bank ensconced in another store.

But Patrica Dunphy, who handles retail leasing for Rockrose, said she always had her eye on the privately-owned buybuyBaby.

The company started with one store in Rockville, Maryland and Dunphy watched the chain circle the city, opening stores in Scarsdale, Paramus, N.J., and two on Long Island, like other moms, using their gift registry and other services.

When Lechter’s gave up its lease, Dunphy turned to retail brokers Howard Gilbert and Robert K. Futterman of Robert K. Futterman & Associates.

They represented the Garden City, L.I.-based buybuyBaby, which was finally ready to make it in Manhattan.

When it opens in September it will become the chain’s sixth store and the area’s largest baby store.

“They were waiting for the time to be right,” said Gilbert.

Jeffrey Feinstein, head of buybuyBaby, did not return calls before deadline.